Pre-Amplifier SPA Series
• External Pre-Amplifier for all A/D cards
• Low noise/high gain
• Allows to acquire smallest signals
with high resolution
• 5 different versions
• 20 dB to 60 dB gain
• up to 500 MHz bandwidth
• AC/DC coupling
• Manual offset compensation
• No programming necessary
General Information
Very low Input Noise
Although all Spectrum A/D cards have a very powerful input section with a highly configurable input amplifier and a variety of input ranges it is sometimes
necessary to have additional external amplifiers if the
signal to acquire has an extremely low level. Spectrum
offers a range of perfectly matching external amplifiers to cover such cases. These powerful amplifiers
have been rated using the Spectrum cards and offer
best performance together with high amplification
rates.
Low input noise is very important for a good signal-to-noise ratio, especially when
amplifying small signals. All SPA Amplifiers are optimized for minimum input
noise reaching excellent values as low as 0.9 nV/√Hz.
The amplifiers are simply connected between the signal source and the Spectrum A/D card input and can
be manually switched between different settings using
small lever keys. All amplifiers allow the offset compensation by using an adjustable screw.
Bandwidth
For optimum signal-to-noise performance choose an
amplifier with sufficient bandwidth corresponding to
the required signal bandwidth. However, keep in
mind that unnecessary high bandwidth introduces
more wideband noise. Therefore, Spectrum offers SPA
Voltage Amplifiers with three different upper cut-off
frequencies to match individual measurement requirements. The bandwidth remains constant when switching between the different gain settings which is very
important for measuring fast signals and pulses.
True DC with zero output offset
True DC-Coupling is extremely important for accurate
pulse amplification and analysis especially when different pulse lengths occur like in digital codes or transients with micro- to millisecond duration. If the
amplifier is AC coupled or has a large output offset to
be de-coupled by the AC setting of the oscilloscope
there will be significant undershoots and baseline
shifts in the measurements. Therefore, all SPA Amplifiers offer a true DC coupling and an adjustable output
offset control even with the 500 MHz model.
Technical Data
Model
Lower cut-off frequency
Upper cut-off frequency
Rise/Fall Time 10-90%
Gain (dB)
Gain (amplification)
Gain Accuracy
Input Volt.Noise (20
dB)
Input Volt.Noise (40
dB)
Input Volt.Noise (60
dB)
Input Bias Current
Input Offset Voltage
Input Voltage Drift
Input Impedance
Input Coupling
Max Input Voltage
Dimension
Weight
SPA.1601
DC
500 MHz
750 ps
20 dB
x10
±0.2 dB
SPA.1412
DC /1 Hz
200 MHz
1.8 ns
20/40 dB
x10/x100
±0.2 dB
SPA.1411
DC / 1 kHz
200 MHz
1.8 ns
20/40 dB
x10/x100
±0.2 dB
1.2 nV/√Hz
SPA.1232
DC / 1 Hz
10 MHz
35 ns
40/60 dB
x100/x1000
±0.2 dB
n.a.
SPA.1231
DC / 1 kHz
10 MHz
35 ns
40/60 dB
x100/x1000
±0.2 dB
n.a.
3.0 nV/√Hz
4.5 nV/√Hz
n.a.
5.5 nV/√Hz
3.5 nV/√Hz
4.7 nV/√Hz
1.8 nV/√Hz
n.a.
n.a.
n.a.
4.7 nV/√Hz
0.9 nV/√Hz
15 µA typ
1 mV typ
10 uV/°C
50 Ω
10 pA
500 uV typ
5 uV/°C
1 MΩ
15 pF
20 µA
2 pA
500 uV typ
250 uV max
1 uV/°C
2 uV/°C
50 Ω
1 MΩ
12 pF
15 pF
±5 V
94 mm x 51 mm x 27 mm
200 grams
18 µA typ.
500 uV max
1 uV/°C
50 Ω
12 pF
Order and Delivery Information
The SPA amplifier is delivered with an external power
supply. The power supply
covers 100 to 240 VAC with
50 to 60 Hz.
The SPA amplifier has female
BNC connectors on both the
input and output. Please be
sure to order an adapter cable that has a male BNC connector and matching
connector type for your A/D
card input.
SPECTRUM SYSTEMENTWICKLUNG MICROELECTRONIC GMBH · AHRENSFELDER WEG 13-17 · 22927 GROSSHANSDORF · GERMANY
PHONE: +49 (0)4102-6956-0 · FAX: +49 (0)4102-6956-66 · E-MAIL: [email protected] · INTERNET: http://www.spectrum-instrumentation.com
16.12.14
Measuring Results
Measuring Results
These measurings have been taken using a M3i.4140 (1 channel 14 bit 400 MS/s digitizer with 200 MHz bandwidth) from series production. All measurings have been done using the +/-500 mV input range with 50 Ohm termination. The amplifer was also connected to this
input range. For the dynamic paramter measurements a pure sine wave signal from a RF signal generator in combination with a matching
7th order low pass filter (1 MHz and 9 MHz plots) was used. For reference the same measuring results with and without the amplifier are
shown.
Results shown here are typical values which may vary from card to card and may depend on the environment.
Input Noise Level (Open Inputs)
Card with no amplifier ->±500 mV input
Card with SPA.1411 (200 MHz, 50Ω amp), 20 dB -> ±50 mV input
Card with SPA.1411 (200 MHz, 1MΩ amp), 20 dB -> ±50 mV input
Card with SPA.1411 (200 MHz, 50Ω amp), 40 dB ->±5 mV input
Card with SPA.1411 (200 MHz, 1MΩ amp), 40 dB ->±5 mV input
2
Insert document name here
Measuring Results
1 MHz sine wave signal with 95% output level
Card with no amplifier ->±500 mV input
SNR = 66.7 dB, THD = -80.6 dB, ENOB = 10.8 LSB
Card with SPA.1411 (200 MHz, 50Ω amp), 20 dB ->±50 mV input
SNR = 56.7 dB, THD = -72.4 dB, ENOB = 9.1 LSB
Card with SPA.1412 (200 MHz, 1MΩ amp), 20 dB ->±50 mV input
SNR = 52.4 dB, THD = -67.1 dB, ENOB = 8.4 LSB
Card with SPA.1411 (200 MHz, 50Ω amp), 40 dB ->±5 mV input
SNR = 44.5 dB, THD = -61.2 dB, ENOB = 7.1 LSB
Card with SPA.1412 (200 MHz, 1MΩ amp), 20 dB ->±5 mV input
SNR = 34.4 dB, THD = -50.0 dB, ENOB = 5.4 LSB
(c) Spectrum GmbH
3
Measuring Results
9 MHz sine wave signal with 95% output level
Card with no amplifier ->±500 mV input
SNR = 65.9 dB, THD = -81.8 dB, ENOB = 10.6 LSB
Card with SPA.1411 (200 MHz, 50Ω amp), 20 dB ->±50 mV input
SNR = 56.1 dB, THD = -60.9 dB, ENOB = 9.0 LSB
Card with SPA.1412 (200 MHz, 1MΩ amp), 20 dB ->±50 mV input
SNR = 52.0 dB, THD = -61.0 dB, ENOB = 8.3 LSB
Card with SPA.1411 (200 MHz, 50Ω amp), 40 dB ->±5 mV input
SNR = 44.0 dB, THD = -59.0 dB, ENOB = 7.0 LSB
Card with SPA.1412 (200 MHz, 1MΩ amp), 20 dB ->±5 mV input
SNR = 33.4 dB, THD = -49.3 dB, ENOB = 5.3 LSB
4
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Measuring Results
40 MHz sine wave signal with 95% output level
Card with no amplifier ->±500 mV input
SNR = 66.2 dB, THD = -72.8 dB, ENOB = 10.7 LSB
Card with SPA.1411 (200 MHz, 50Ω amp), 20 dB ->±50 mV input
SNR = 56.0 dB, THD = -47.0 dB, ENOB = 9.0 LSB
Card with SPA.1412 (200 MHz, 1MΩ amp), 20 dB ->±50 mV input
SNR = 51.1 dB, THD = -50.1 dB, ENOB = 8.2 LSB
Card with SPA.1411 (200 MHz, 50Ω amp), 40 dB ->±5 mV input
SNR = 43.6 dB, THD = -49.8 dB, ENOB = 6.9 LSB
Card with SPA.1412 (200 MHz, 1MΩ amp), 20 dB ->±5 mV input
SNR = 31.9 dB, THD = -49.4 dB, ENOB = 5.0 LSB
Order Information
Amplifiers
Order no.
Bandwidth
SPA.1601 (2)
SPA.1412 (2)
SPA.1411 (2)
SPA.1232 (2)
SPA.1231 (2)
Information
500 MHz
50 Ohm
DC
x10 (20 dB)
200 MHz
1 MOhm
AC/DC
x10/x100 (20/40 dB)
200 MHz
50 Ohm
AC/DC
x10/x100 (20/40 dB)
10 MHz
1 MOhm
AC/DC
x100/x1000 (40/60 dB)
10 MHz
50 Ohm
AC/DC
x100/x1000 (40/60 dB)
External Amplifiers with one channel, BNC female connections on input and outpu, manually adjustable offset, manually switch between settings. An external power supply for 100 to 240 VAC is
included. Please be sure to order an adapter cable that has a male BNC connector and matching connector type for your A/D card input..
Input Impedance
Coupling
Amplification
(1) : Just one of the options can be installed on a card at a time.
(2) : Third party product with warranty differing from our export conditions. No volume rebate possible.
(c) Spectrum GmbH
5

Lecture 16 Notes